chore[GH-#849]: Add unit test for imageElement (#1502)

webapp/src/components/content/__snapshots__/imageElement.test.tsx.snap

@@ -0,0 +1,11 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`components/content/ImageElement should match snapshot 1`] = `
+<div>
+  <img
+    alt="test-title"
+    class="ImageElement"
+    src="test.jpg"
+  />
+</div>
+`;

webapp/src/components/content/imageElement.test.tsx

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+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+import React from 'react'
+import {render} from '@testing-library/react'
+
+import {act} from 'react-dom/test-utils'
+
+import {mocked} from 'ts-jest/utils'
+
+import {ImageBlock} from '../../blocks/imageBlock'
+
+import {wrapIntl} from '../../testUtils'
+
+import octoClient from '../../octoClient'
+
+import ImageElement from './imageElement'
+
+jest.mock('../../octoClient')
+const mockedOcto = mocked(octoClient, true)
+mockedOcto.getFileAsDataUrl.mockResolvedValue('test.jpg')
+
+describe('components/content/ImageElement', () => {
+    const defaultBlock: ImageBlock = {
+        id: 'test-id',
+        workspaceId: '',
+        parentId: '',
+        rootId: '1',
+        modifiedBy: 'test-user-id',
+        schema: 0,
+        type: 'image',
+        title: 'test-title',
+        fields: {
+            fileId: 'test.jpg',
+        },
+        createdBy: 'test-user-id',
+        createAt: 0,
+        updateAt: 0,
+        deleteAt: 0,
+    }
+
+    test('should match snapshot', async () => {
+        const component = wrapIntl(
+            <ImageElement
+                block={defaultBlock}
+            />,
+        )
+        let imageContainer: Element | undefined
+        await act(async () => {
+            const {container} = render(component)
+            imageContainer = container
+        })
+        expect(imageContainer).toMatchSnapshot()
+    })
+})